Method of making brushes



April 20, 1943. Ev RPERSQN 2,317,110

M ETHOD OF MAKING BRUSHES Filed Aug. 4, 1938 2 Sheets-Sheet 2 J7 *JQ 44 J7 r o y o o f @lmw@ ,o o o o" o o o -I7 Z0 16j/9,5.

2 v117 17 ,J6 ,[7 J7 Patented Apr. 20, 1943 UNITED STATES PATENT OFFICE 2,317,110 METHOD F MAKING BRUSHES Earl It. Person, Leominster, Mass., assignor to E. l. du Pont de Nemours & Company, Wilminp. ton, Del., a corporation oi' Delaware Application August 4, 1938, Serial No. 223,102

Z Claims.

This invention relates to the manufacture of brushes and other articles by the previous placing of the bristles, or the like, in the desired pattern and the sealing of said bristles by the flow of plastic or liquid material around them in dies.

The principal object of the invention is to set the bristles into the form with the ends projecting into it, but not all the way through it, and then ow the material of the handle around the ends of the bristles, thus forming the handle and sealing the bristles at the same time.

Other objects of the invention are to provide one or more inserts to be placed between the dies and perforated to hold the ends of the bristles,

or whatever articles are to be joined to the main part of the device, and to flow the plastic around the insert and the ends of the bristles so as to form the brush handleand holding means for the bristles in one operation, and to reduce the time of manufacture of tooth brushes or other similar articles.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings, in which Fig. 1 is a longitudinal central sectional view showing the bristles set into the preliminary dies;

Fig. 2 is a similar view, with the dies inverted and an outside or backing die in place and spacing the ends of the bristles from the back of the die;

Fig. 3 is a similar view showing the dies with the brush back and handle molded therein;

Fig. 4 is a longitudinal sectional view of a set of dies with an insert in position, ready for receiving the bristles:

Fig. 5 is a plan of one form of insert that can be used;

Fig. 6 is an edge view of the same, as indicated by the arrow 6 in Fig. 5;

Fig. I is a plan of another form of insert com- -ing within the scope of this invention;

Fig. 8 is a longitudinal central sectional view of the same as indicated by the line 8-8 of Fig. 7, and

Fig. 9 is a longitudinal sectional view of the set of dies inverted and the bristles in place ready for the receipt of the plastic material. l

Referring to Figs. 1, 2 and 3, it will be seen that three consecutive steps of the manufacture of a brush are illustrated according to this inventlon. In Fig. 1^diev parts I and 2 are shown of which the part I is a die only in the sense that it stops and holds the ends of the bristles. They are fed and arranged in any usual or other manner through passages 4 in the die part 2. Thus their ends are uniformly located and their main bodies are held in the holes 4, temporarily, in any 4desired manner.

Now the parts I and 2 are inverted, the part I removed, and a die part 5 located in its place. It will be seen now that the two parts I and 5 are exactly alike, except that the die cavity 6 is cut in the part 5. This leaves a space 1 for the plastic material 8 to flow and remain beyond the inner ends of the bristles. Thus the bristles cannot project to the back surface of the brush, as appears in Fig. 3.

Referring to Fig. 4, a stationary half II) of the die is shown cooperating with a removable half 26 of the die. 'It will be noticed that one of a plurality of dowel pins I2 is shown for holding the two die halves together.

When these parts are employed for producing a tooth brush, hair brush, or the like, one or more inserts Il, if used, are placed in the die cavity I5 between the two dies I0 and 26. As shown, a single insert is employed having perforations I6 therein into which the butt ends of the single bristles are introduced, from above through holes in the die I0, to form the necessary number of tufts of bristles. These tufts can be inserted by using a shaking machin:

It will be noticed that the insert is provided with several projections I'I which extend across the die cavity so as to engage in depressions 25 in the concave surface of the die 28.

The tufts having been assembled in the manner shown in Fig. 4, the whole device is turned over, the die 26 removed .and replaced by a new die II which has a deeper cavity to just receive the projection I1. The whole device is supported on a base I3 as shown in Fig. 9. Now the pyroxoline, or other material, which can be reduced by heat to a liquid or plastic state, is forced in under some pressure, preferably from the opposite end of the cavity to that shown, namely into the handle part of the brush. This substance will come into contact with the bristles where they project at the back of the insert and will entirely surround the insert and all exposed surfaces thereof. It will then harden and hold the insert and the bristles firmly in place.

The insert can be made of the same material as that which is employed for making the brush handle and the other parts oi' the brush,'shown as filled in Fig. 9. The brush can be removed from the dies, taking the bristles with it and the brush is completed except for such polishing as might be required.

' The insert Il illustrated in Fig. 4 is also shown separate in Figs. 5 and 6. In this case the insert has transverse projections I9 from a concave but substantially uniform back 2l and the material can flow all around it as the filling material is introduced into the dies under some degree of pressure.` This provides for several rows in the present instance, arranged three in a row and at such angles andin such relationship as is provided by the insert.

In Figs. 'I and 8 another form of insert is shown having not only the three projections |11,

shown in the other figures, but also corresponding projections 2| on the back, leaving spaces 22 and 2l on the back and front respectively. Into these spaces the nlling material enters and easily passes into al1 the interstices in the insert as well as completing the brush end of the brush.v

Of course, the handle end is made simultaneously and the handle is integral with the brush end.

Having thus described my invention and the' advantages thereof, I do not wish to be limited tothe details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. 'I'he method of making a tooth brush, which consists in providing a die vpart having perforations extending therethrough, filling the periorations with bristles extending through the perforations and projecting beyond them, placing the die part over a second die part having a surface spaced from the first die part to limit the projection of the bristles beyond the firstvdie part,` inverting both die parts as one piece. removing the die part now at the top. replacing it by a third die part having a die slufaoe farther from the surface of the nrstdie part to allow a" plastic material to cQYerthQPIQJWmR endl 0! the bristles, and illling the cavity between the two die parts with a plastic material. a.

2. The method of making a brush, which consists in providing a die part having perforations extending therethrough, inserting in the perforations tufts of bristles extending through the perforations and prOJQQtinU beyond them, placing the die part against a second die part having a surface spaced from the ilrst die part .to 

